Wafer-maker Siltronic Corp. bought 446 million gallons of water from Portland during the last fiscal year, enough to fill an Olympic-sized swimming pool twice a day for almost an entire year.

For context, it would take a typical Portland family 15 years to fill that same swimming pool just once.

“We obviously are the biggest user,” said Myron Burr, Siltronic’s senior manager for environmental health safety, noting that the company uses about 1.5 percent of all Portland water.

The company’s massive water consumption is necessary to clean the silicon wafers manufactured at its campus along the Willamette River. Siltronic switched from a chemical treatment process in the 1980s, but even Portland’s pristine Bull Run water isn’t good enough for the high-tech world, which buys the company's wafers for computer chips and the like.

View full sizeSilicon wafers with diameter from 76 to 300 mm. The German company cited decreasing demand when it cut 350 jobs from its Portland plant in 2012.Siltronic AG

Siltronic needs “ultra pure water,” Burr said.

Pipes push Portland’s water to the Siltronic campus, where it goes through a number of purification steps to remove minerals and chlorine. From there, the water is pumped over to the fab, or factory, where cassettes of 8-inch-diameter wafers are dumped into baths dozens of times throughout the production process.

Burr said Siltronic has reduced water consumption by about 25 percent per unit produced during the past 15 years. But Burr said the company can’t make up ground when rates go up as fast as they have.

“You can’t get ahead of the curve,” he said.

More than any other commercial or residential customer, Siltronic stands to benefit the most financially from changes to water rates simply because of the company’s staggering consumption.

For most individuals and businesses, Portland’s sewer bill is the real killer, accounting for about two-thirds of city utility charges.

Portland tracks water consumption but, in most instances, not sewer discharge. The city uses water as a proxy for sewer use, figuring what comes into a home or business is a good representation of what goes out. Sewer and stormwater bills are more expensive than water. That means using a lot of water has a big multiplier effect on the total bill, when sewer is factored in.

But Siltronic, like some other businesses, has a separate sewer meter that keeps track of output. And the company has its own waste treatment plant. That explains why Siltronic had $2 million in water charges but just – and we’re using the term “just” in context here -- $1.4 million in sewer billing in 2012-13.

“We’re in a very competitive business,” Burr said. “We’re doing what we can to control our costs. We’re supportive of a system that we think would be more cost conscious.”